Why do we war?

Jonathan Bastian talks with Margaret MacMillan, historian and author of “War: How Conflict Shaped Us,” about how war has defined our lives and our culture. Later, Edward Tick, psychotherapist, poet and author of “Warrior's Return: Restoring the Soul After War,” and Rabbi Steve Leder speak about the invisible wounds of war, the feeling of helplessness in the presence of evil, and building resilience.